BOMBYCmE. 127 



But the shape of the wings is not the only sexual 

 difference. The colours of the male are always 

 darker than those of the female, and the markings 

 on a much smaller scale. Nay, some of the mark- 

 ings found in the one entirely disappear in the 

 other. Thus the female of H. atlas has a small 

 supplemental vitreous spot on the disk of the 

 wings ;* in many of the smaller species the form of 

 the vitreous spaces is quite different in the two 

 sexes ; and there is commonly some additional bar 

 or spots peculiar to the female. In short, when an 

 attempt is made to unite the sexes to their legiti- 

 mate partners, it must be kept in mind that this 

 relationship has often no other external indication 

 than an approximation in size, and a certain gene- 

 ral resemblance in the design and colour of the 

 wings. 



In consequence of these considerations having 

 been overlooked, there is reason to believe that the 

 two sexes have sometimes been described as distinct 

 species. Cramer committed this error in regard to 

 A. erythrince, and it is not surprising that he 

 should have done so, for they are remarkably dis- 

 similar. A fine species from Assam has recently 

 been described by the Rev. F. TV. Hope, under the 

 name of Bomlyx spectabilis^ and figured with his 



* We are informed by Mr. "Westwood that there is an article 

 on the habits and variations of the sex of H. atlas in the " Actes 

 de la Societe Linneenne de Bourdeanx, t. iv. 3d levraison. 

 June 1830 :" a work which we have not had an opportunity 

 of consulting. 



